From patchwork Tue May 22 18:03:42 2012
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Subject: mtd: ABI documentation: clarification of bitflip_threshold
From: Mike Dunn
X-Patchwork-Id: 160713
Message-Id: <1337709822-11587-1-git-send-email-mikedunn@newsguy.com>
To: linux-mtd@lists.infradead.org
Cc: Mike Dunn
Date: Tue, 22 May 2012 11:03:42 -0700
The -EUCLEAN return value applies to mtd_read_oob() as well as mtd_read(), but
only mtd_read() was mentioned in the blurd on bitflip_threshold in the ABI
documentation.
Signed-off-by: Mike Dunn
---
Sorry to keep revisiting this, but this seems like a big omission. It looks
like a big rewrite because of reformatting, but only the words "and
mtd_read_oob()" are added to the first paragraph. I deliberately left ambiguous
the question of whether -EUCLEAN can be returned if mtd_read_oob() is used to
read oob-only ;)
Documentation/ABI/testing/sysfs-class-mtd | 17 +++++++++--------
1 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-class-mtd b/Documentation/ABI/testing/sysfs-class-mtd
index db1ad7e..938ef71 100644
--- a/Documentation/ABI/testing/sysfs-class-mtd
+++ b/Documentation/ABI/testing/sysfs-class-mtd
@@ -142,13 +142,14 @@ KernelVersion: 3.4
Contact: linux-mtd@lists.infradead.org
Description:
This allows the user to examine and adjust the criteria by which
- mtd returns -EUCLEAN from mtd_read(). If the maximum number of
- bit errors that were corrected on any single region comprising
- an ecc step (as reported by the driver) equals or exceeds this
- value, -EUCLEAN is returned. Otherwise, absent an error, 0 is
- returned. Higher layers (e.g., UBI) use this return code as an
- indication that an erase block may be degrading and should be
- scrutinized as a candidate for being marked as bad.
+ mtd returns -EUCLEAN from mtd_read() and mtd_read_oob(). If the
+ maximum number of bit errors that were corrected on any single
+ region comprising an ecc step (as reported by the driver) equals
+ or exceeds this value, -EUCLEAN is returned. Otherwise, absent
+ an error, 0 is returned. Higher layers (e.g., UBI) use this
+ return code as an indication that an erase block may be
+ degrading and should be scrutinized as a candidate for being
+ marked as bad.
The initial value may be specified by the flash device driver.
If not, then the default value is ecc_strength.
@@ -167,7 +168,7 @@ Description:
block degradation, but high enough to avoid the consequences of
a persistent return value of -EUCLEAN on devices where sticky
bitflips occur. Note that if bitflip_threshold exceeds
- ecc_strength, -EUCLEAN is never returned by mtd_read().
+ ecc_strength, -EUCLEAN is never returned by the read operations.
Conversely, if bitflip_threshold is zero, -EUCLEAN is always
returned, absent a hard error.